She's been tied to an old tree stump with her arms at her side and really no possibility of getting free. Firewood is piled around her and a couple of flasks of oil have been smashed over it before it's lit. She's going to spend some time on the fire, so just what will happen to her?
Obviously she's going to be very badly burned - which parts would be worse? She was standing on the ground before the wood was piled around her. Some of the oil soaked into her clothes so that's going to burn very quickly, but most of her clothes are wool. How does wool burn? What about cotton? How about her hair?
She's going to inhale a lot of smoke. What will this do to her lungs? To her eyes?
I know fire can numb pain by destroying nerves. Just how much is this going to hurt? What does burning human flesh smell like?
After all this she needs to be rescued. What kind of precautions would her rescuer need to take when carrying her? (She'll be unconscious at this point). How can they avoid catching fire themself? This is a fantasy setting with no modern healthcare, so what kind of things could a healer do for her? What kind of scars and permanent injuries would be left behind? Her rescuer has magical healing skills but I'd rather use as little of that as possible while still keeping her alive.
For some reason all I'm finding with google is sites about spontaneous human combustion, forest fires and country and western music.